1. Field of the Invention
The present invention relates to novel precipitated silica particulates, to a process for the preparation thereof, and to the use of such novel silica particulates as a reinforcing material for elastomeric matrices.
2. Description of the Prior Art
It is known to this art that precipitated silica is a useful reinforcing filler for elastomeric matrices.
However, as with any reinforcing filler, it must be easily manipulated and readily incorporated into the material to be reinforced.
Silica typically exists in the form of a powder. However, such powder form is not completely satisfactory in that it generates large amounts of dust and is incorporated into the matrix only slowly (low apparent density).
For this reason, silica in granulated form has been proposed to the art, which conveniently resolves the aforementioned problems, but which frequently results in an insufficient dispersion of the filler in the elastomers and provides a lesser degree of reinforcement relative to a filler in the powder form.
To obviate this disadvantage, EP 18,866, assigned to the assignee hereof, proposed certain homogeneous silica spheres having a mean particle size greater than 80 .mu.m, a BET surface area of 100 to 300 m.sup.2 /g and a density of approximately 0.29.
This type of silica material has been found to be particularly advantageous in light of its elastomer reinforcing properties.
However, there is an existing need in this art to still further improve these materials relative to one or more of their characteristics/properties. For example, need continues to exist for silica particulates which are well dispersed in elastomers and, in particular, have a higher density.